JP-A-2000-334259 describes an apparatus that carries out separation and recovery of nitrogen oxides (NOx) relative to gas exhausted from a chemical plant or car. The apparatus stores a liquid in a cleaning device, and the liquid is able to absorb a substance, such as NOx, to be separated and recovered. The NOx is removed from the exhausted gas by introducing the exhausted gas into the cleaning device and by agitating the liquid.
The apparatus further includes a cooling device that cools the liquid, so that the liquid is restricted from evaporating even when the exhausted gas has high temperature. Generally, the liquid, which absorbs NOx, is water or alkaline aqueous solution, for example.
However, when NOx is absorbed by the easily-evaporating liquid such as water or alkaline aqueous solution, such a cooling device is necessary for restricting the evaporation of the liquid, so that a size of the apparatus may be made larger. Moreover, the absorption density of NOx is not so much high in water or alkaline aqueous solution.
If the apparatus is applied to a car, for example, the car is required to be equipped with the large apparatus, which stores a large amount of the liquid, or the car is required to be frequently supplied with the liquid, so that the practical applicability may be low.